Evidence for Genetic Variation in Resistance to a Respiratory Infection in Chickens

GENETIC differences in resistance to different infectious diseases of chickens have been extensively studied by a large number of investigators. Since Hutt (1949) has recently reviewed the field it is not necessary to cover the same ground here, except to list the particular diseases for which genetic information is available. They include avian diphtheria (Frateur, 1924), fowl typhoid (Lambert and Knox, 1932), pullorum (Roberts and Card, 1935), and lymphomatosis (Asmundson and Biely, 1932; Taylor, Lerner, DeOme and Beach, 1943; Hutt and Cole, 1948; and many others). Although the various respiratory diseases to which chickens are subject are extremely common in the field, so far apparently no demonstration of genetic variation in resistance to any of them has appeared in the literature. The purpose of the present report is to record the evidence for the existence of such variation in the University of California flock of Single Comb White Leghorns. This . . .